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SubjectRe: [PATCH 14/38] clk: vt8500: fix sign of possible PLL values
On 09/21, Andrzej Hajda wrote:
> With unsigned values underflow in loops can occur resulting in
> theoretically infinite loops.
>
> The problem has been detected using proposed semantic patch
> scripts/coccinelle/tests/unsigned_lesser_than_zero.cocci [1].
>
> [1]: http://permalink.gmane.org/gmane.linux.kernel/2038576
>
> Signed-off-by: Andrzej Hajda <a.hajda@samsung.com>
> ---
> drivers/clk/clk-vt8500.c | 6 +++---
> 1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/clk/clk-vt8500.c b/drivers/clk/clk-vt8500.c
> index 37e9288..098e9fa 100644
> --- a/drivers/clk/clk-vt8500.c
> +++ b/drivers/clk/clk-vt8500.c
> @@ -384,7 +384,7 @@ static void vt8500_find_pll_bits(unsigned long rate, unsigned long parent_rate,
> static void wm8650_find_pll_bits(unsigned long rate, unsigned long parent_rate,
> u32 *multiplier, u32 *divisor1, u32 *divisor2)
> {
> - u32 mul, div1, div2;
> + int mul, div1, div2;

Only div2 seems to need the treatment here.

> u32 best_mul, best_div1, best_div2;
> unsigned long tclk, rate_err, best_err;
>
> @@ -452,7 +452,7 @@ static u32 wm8750_get_filter(u32 parent_rate, u32 divisor1)
> static void wm8750_find_pll_bits(unsigned long rate, unsigned long parent_rate,
> u32 *filter, u32 *multiplier, u32 *divisor1, u32 *divisor2)
> {
> - u32 mul, div1, div2;
> + int mul, div1, div2;

And here div1 and div2 are the only ones.

> u32 best_mul, best_div1, best_div2;
> unsigned long tclk, rate_err, best_err;
>
> @@ -496,7 +496,7 @@ static void wm8750_find_pll_bits(unsigned long rate, unsigned long parent_rate,
> static void wm8850_find_pll_bits(unsigned long rate, unsigned long parent_rate,
> u32 *multiplier, u32 *divisor1, u32 *divisor2)
> {
> - u32 mul, div1, div2;
> + int mul, div1, div2;

And div1 and div2 here.

Can we focus the changes on the actual problematic variables? I
suppose this has never mattered because we break out of these
loops.

--
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum,
a Linux Foundation Collaborative Project


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